Public
Part of speech: noun
Definition: The people in general, regardless of membership of any particular group.
Part of speech: adjective
Definition: Pertaining to the affairs or official affairs of all people, not just those of a private group; contrasted with private. Open to all. Funded by the government. Traded publicly via a stock market.
Example sentence: We hang the petty thieves and appoint the great ones to public office.
World
Part of speech: noun
Definition: Human collective existence; existence in general.The Universe.The earth.A planet,especially one which is inhabited or inhabitable.An individual or group perspective or social setting.A great amount.
Example sentence: Do your little bit of good where you are; it's those little bits of good put together that overwhelm the world.